


overachiever

by titaniumexpose



Category: Day6 (Band)
Genre: Accidental Voyeurism, Awkward Conversations, Begging, Come Eating, Come Swallowing, Deepthroating, Dom/sub Undertones, Explicit Sexual Content, Fantasizing, M/M, Oral Sex, Overstimulation, Plot What Plot/Porn Without Plot, Resolved Sexual Tension, Size Kink
Language: English
Status: Completed
Published: 2020-12-07
Updated: 2020-12-07
Packaged: 2021-03-09 21:33:21
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,423
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27933124
Author URL: https://archiveofourown.org/users/titaniumexpose/pseuds/titaniumexpose
Summary: Younghyun knows these things about himself: he’s a man of particular interests and he appreciates a good challenge. These are the reasons why his roommate Sungjin has got him in such a bind.
Relationships: Kang Younghyun | Young K/Park Sungjin
Comments: 3
Kudos: 47





	overachiever

**Author's Note:**

> No thinking, just sex

Younghyun has always known himself to be a man of particular interests. Give him any topic—whether it be music or photography or books—and he would have an opinion on the matter. A side that he favored. As far as genres of music go, it would always be rock for him. For instruments, guitar and bass are enough. As for photography, he’s always liked shooting landscapes and scenery more than people. And for books, he is strictly a reader of fiction—he already has enough of the real world to deal with that he doesn’t want to _read_ about it, too.

He has also realized early on that his being of particular interests extended to other parts of his life. Parts such as: his interest in men. Or specifically, their dicks. For as long as he has been sure of his sexuality, he’s had a particular type. Forgive him for the cliché, but he truly does like it big. The bigger, the better—the more desperate Younghyun gets. He is not above begging for a fat cock.

It isn’t like the fascination most people have with big dicks, he thinks, because theirs is a fascination that quickly wanes when they realize how demanding it is to take one. How much it burns as it stretches one open, or how difficult it is to swallow down. Big dicks are appealing in theory, but most people find they’re not worth the hassle in reality.

The things that discourage most people only serve to turn Younghyun on. The work that comes with pleasuring a big cock is part of its charm. Younghyun likes everything to do with a big cock, but he loves it the most when it’s in his mouth. He likes to push himself to the limit and take it all the way up to the hilt; likes to feel his jaw creak with exertion as he bobs on the cock like it’s all he was born to do; likes it when a man with a fat cock fucks his mouth for all it’s worth. Likes to look up and see that same expression, slack-jawed with their eyes rolling back, before it turns mad with pleasure as they come—down Younghyun’s throat, in his mouth, or on his face. It doesn’t matter. It’s the same rush he gets every time.

Younghyun’s particular tastes has led him to a problem concerning Sungjin, his roommate of one year. It’s not a problem that Sungjin personally has anything to do with, no; this problem is purely because Younghyun has a dirty mind and Sungjin, just by being himself, makes all the gears in it turn.

The problem rests on this premise: Sungjin is big. Broad. So much of a manly man that he makes Younghyun doubt himself sometimes. But Sungjin isn’t scary or intimidating past the first meeting. He’s big and tough, but he’s more like a giant teddy bear than anything else. A giant teddy bear that has a knack for cleaning on weekends, likes to nag Younghyun when he forgets to eat, and visits his family in Busan every month without fail.

And yet. In spite of all these things, Sungjin is still big. He’s a bit shorter than Younghyun, but he’s wide. He doesn’t go to the gym all that much, but he plays practically every sport under the sun and it shows. It really does, in the cut of his biceps and the curve of his calves. Sungjin is sturdily built, with big hands and feet—hell, even a big _nose_ —and Younghyun knows what they all say about men like that.

On some mornings, Younghyun would find his roommate wearing nothing but boxers as he looks for something to eat. And Younghyun would wonder. _Is Sungjin big where it counts, too?_

He doesn’t know for sure, but his mind definitely thinks it knows the answer, and these thoughts keep him up at night.

Younghyun has never imagined he’d get the chance to find out, but one afternoon he finishes his project in the studio earlier than expected, so he logs out and leaves before his reservation ends. In doing so, he forgets to text Sungjin that he’s already on the way home—their shared apartment is a mere three blocks away from the studio, and Younghyun has always appreciated the light exercise.

He never imagined he’d get to find out, because Sungjin has never once alluded to his sex life, or even his relationships, in their time as roommates. And it’s with this certain reassurance that Younghyun fishes his keychain out of his backpack, unlocks the door to their apartment, and crosses the short distance between their living room and the door to their shared bedroom—

Only to find Sungjin on his bed half-naked with one hand around his cock. His eyes are closed, the expression on his face that of quiet pleasure.

Younghyun’s mouth opens of its own accord. “Oh my god!”

Sungjin’s eyes fly open to find him in the doorway. “Fuck, Kang Bra—”

“I’m _so_ sorry!”

Younghyun slams the door back shut and, possessed by some unknown power, he runs out of their shared apartment and down the building’s stairs. He doesn’t even register his shortness of breath, the way his legs are shaking. He just runs, holding on with a death grip to the straps of his backpack, to the first destination his mind can offer: the studio.

As Younghyun makes his mad dash back, the only thing on his mind is: _he’s big. Fuck. Sungjin-hyung is big._ And Younghyun knows that this is true because Sungjin has big hands, but his cock still looked huge in his grip. And Sungjin’s cock… the head was red and surprisingly uncut. And maybe it was just a trick of the light but Younghyun swears the tip was wet and weeping.

Younghyun can’t help it: he imagines. How would Sungjin’s cock look like in his hand? He has smaller hands than Sungjin—would they make Sungjin’s cock look even bigger? If Younghyun wraps both of them around his cock, would they be enough to cover it entirely? Or would the head still peek out? If he lets Sungjin’s cock go, how would it look like against the backdrop of Sungjin’s pale stomach?

When Younghyun gets to the studio, he throws its doors wide open, not even bothering to sign in at the counter. It’s a small miracle that there’s no one else around, because that means there’s no one to see him as he makes a break towards the nearest comfort room.

How would Sungjin feel on his tongue? In his throat? He knows Sungjin would fill him up good, but aside from that… Would Sungjin be the type to go slow, or would he lay claim to Younghyun’s mouth with no hesitation? Once Younghyun’s taken him all the way in, what would he smell on Sungjin’s skin? Would he smell a bit of Sungjin’s spearmint soap or his expensive perfume, or would the musk of Sungjin’s sweat and cock overwhelm Younghyun’s senses?

He runs into the first empty stall he finds, closing it so fast that he nearly crushes his thumb. As he slides the lock into place, he hopes to all hell that there’s no one else around. There can’t be any witnesses, not when he’s about to have the most embarrassing wank of his life.

Younghyun tugs his cock out, already half-hard and pearling at the tip. He spits in his hand before taking himself in his grip.

 _Fuck. Sungjin._ His hot roommate with the big, thick cock. Younghyun is a terrible person for this, but he is no stranger to fantasizing about Sungjin, and he’s always envisioned him as being well-endowed. Everything about Sungjin is big; doesn’t it stand to reason his dick would be, too? But imagining and knowing are two very different things, and right now, Younghyun’s strokes seem particularly desperate.

He lets his mind run some more. What would Sungjin’s come taste like? How much would he release; could Younghyun swallow it all down or would it leak past his lips? And fuck, what kind of sounds would Sungjin make as he comes in his mouth?

Younghyun only has to imagine the way Sungjin’s lovely voice would break around his name and he’s coming in seconds.

He catches his breath for a bare moment before his higher brain functions decide to kick in again. The shame slams into him with the force of a wave. Oh, god. That was stupid. More than that, it was unethical. Getting hard and jacking off to Sungjin, whom he’d found in a compromising situation—what the _fuck_ was Younghyun thinking?

He wasn’t thinking at all, is the answer that comes to him readily. He wipes his dick and his hands clean and inspects his clothes for any… _evidence_ as to what he just did. He was so preoccupied that he didn’t even think about coming into a wad of tissues, and now his shirt has paid the price. He wipes the come off there, too, and dabs the offending areas with a damp tissue once he’s gotten out of the stall.

As Younghyun washes his hands with soap and water, he stares at his reflection in the mirror and thinks, _I am an awful roommate and a terrible human being._ The fluorescent lights above even seem to hum their agreement.

He can’t tell how much time passes but as he waits for his shot nerves to settle in the studio, Sungjin sends him a text. _Hey, is it alright if we talk?_

Actually, what Younghyun would like to do is leave the country and assume a new identity, but he texts back, _Sure, hyung._

Sungjin tells him to come home when he’s ready. In his dread, Younghyun exhausts his studio reservation, eyeing the clock on the wall as it counts down to his last minute. He doesn’t even get anything done; he just sits in the mixing booth and wonders what the hell is going to happen now.

When Younghyun gets back to their apartment, the door is unlocked and Sungjin is already waiting for him on their living room sofa. He looks… contrite. Ashamed. Which is bullshit, because if anyone has cause for shame, it’s only Younghyun.

Younghyun’s ass has no more than touched the sofa when Sungjin launches into his apology. “Younghyun, I’m sorry. I shouldn’t have done _that_ there. Not in a shared space. I should have… conducted my business in the bathroom.”

The formality strikes Younghyun off-balance. _Conducted his business?_ Why does Sungjin sound like he’s talking about taxes? But still—“No, hyung. If anyone has to apologize in this situation, it’s me. I should’ve called to tell you I’d be going home early today.”

Sungjin shakes his head. “No, Younghyun. You don’t have to apologize for anything. I ought to have realized there would always be a chance you would come home early. Your daily schedule is subject to change; I should have been more careful.” He sighs, the strong line of his back sagging in a slouch. “I… I just don’t want you to be uncomfortable, Younghyun-ah.”

“You don’t,” Younghyun blurts out reflexively. “You don’t make me uncomfortable, hyung.” _Actually, what you make me is hard,_ is the thing that goes unsaid. But he continues, “Besides, it’s normal. What you did is normal. People… people wank in their rooms. And um. Just because I share a room with you, doesn’t mean I get to. You know, deprive you of the right to do so.”

 _What the fuck did I just say,_ Younghyun thinks despairingly. Sungjin’s face doesn’t betray a shred of emotion.

“The right,” repeats Sungjin, and then he smiles wryly.

At the very least Younghyun’s remark seems to have defused some of the awkwardness of the situation. “Uh. Yes.”

“To masturbate in the bedroom?”

Younghyun snorts. “I’m not talking about the right to vote, am I?”

“Definitely not,” agrees Sungjin. Pensiveness suddenly clouds his features. “I have a question.”

“Yes?”

“It’s alright if you don’t answer,” Sungjin prefaces hastily. “But… have you ever, um. Exercised that right as well?”

“Oh, yeah,” answers Younghyun shamelessly.

“When I’m not here?” asks Sungjin further.

That, Younghyun can’t answer at all.

In furthering his inquiry, Sungjin seems to have not realized that there are certain questions to which silence is a more transparent answer than words themselves.

“Oh,” Sungjin says, voice small. His mouth, pink and lovely, hangs in a perfect ‘O’ shape of surprise.

“I’m sorry!” wails Younghyun, burying his head in his hands. Speaking to the Sungjin he can see in the gaps between his fingers, he adds, “It’s just. You sleep like a _log,_ Sungjin-hyung.”

 _And he’s got a log for a cock, too,_ his mind unhelpfully supplies.

Sungjin blinks once, twice. “Okay. You’re okay. What you do in your free time is truly none of my business. I apologize for asking.”

“It’s fine, Sungjin-hyung,” murmurs Younghyun. This is the most awkward conversation he’s ever had with anyone. Imploring the heavens, he begs for a bolt of lightning to strike him down where he’s sitting. Nothing of the sort comes.

A week passes. After a day of awkwardness, like they were relearning how to be themselves around each other again, things settle back down to normal.

Or at least, as normal as it can be for Younghyun who still can’t get the image of Sungjin’s cock out of his system.

 _What would it be like,_ his mind wonders in the most inopportune of moments, and what terribly distracting thoughts it conjures.

One night, Younghyun goes to sleep early, a day spent at the studio poring over tracks having tired him out. He barely gets his goodnight out before sleep claims him, and then he’s down for the count.

The difference between him and Sungjin is this: where Sungjin sleeps like a log, Younghyun tosses and turns and wakes up in the middle of the night for no good reason. It usually doesn’t happen when he’s tired but for some reason, it does tonight.

Younghyun is not a heavy sleeper, so he wakes up, groggy, at some indeterminate time. The streetlight outside is a glow coming in through their window—someone must have forgotten to close the blinds. And then he hears something. He doesn’t know what it is for sure.

He props himself up on his right forearm, his eyes finding his roommate in the partial dark. “Hyung?”

“Shit!”

And that’s when Younghyun realizes he’s caught Sungjin in the act again—the same big hand around the same big cock.

Before Sungjin can even cover himself up, Younghyun’s sleep-addled brain decides to go, “Fuck, you’re really that big, huh?” His words come out a moan.

“E-excuse me?”

Younghyun’s hand claps up to cover his mouth. “Holy fuck, I’m so sorry!”

“Did you just say I was big?” asks Sungjin, sounding critical.

It’s not like Younghyun can _lie_ about it. They both have functioning ears. After a moment, he says, “Yes.”

“Huh.”

Awkward silence reigns again. Younghyun takes a look at Sungjin’s face—undecipherable—and then his cock—still hard—before making his mind up.

Screw this if it goes south, but on the off-chance that it doesn’t—“Hyung, can I suck your cock?”

“You _what?_ ” The words sound like they’ve been punched out of Sungjin.

“I mean it,” Younghyun adds earnestly. “I want to suck your cock. Please let me, Sungjin-hyung.”

Sungjin still doesn’t seem to get it. “You want to….”

“Yes, I want to—I’ve wanted to since the first time I saw you,” Younghyun says carelessly. He hadn’t meant to, but he wants to drive the point home. He wants that cock in his mouth.

Sungjin’s eyes widen at his words. At length, he finally concedes. “C’mere, then.” His voice is rough and low.

Younghyun freezes. _Is this really—?_

“Well?” Sungjin shifts, sitting at the edge of the bed, where the light outside better reveals his smirking face, his heavy and straining cock. “It’s not gonna suck itself.”

In an almost dreamlike state, Younghyun scrambles to follow. He leaves his own bed and kneels before Sungjin, hungrily eyeing his prize. He really does have a big dick. It even seems bigger up close. At its base is a thick nest of black hair, and if Younghyun would care to look up a little he’d see it connects with the happy trail that starts below Sungjin’s belly button. As it is, Sungjin’s cock has his full and undivided attention. It’s thick, almost the width of Younghyun’s wrist, and it curves slightly to the left. The head, just as Younghyun remembers, is uncut, but now the foreskin is pushed back, revealing a flushed red head and a slit dribbling with pre-come. All in all, probably nine inches, maybe nine and a half.

“Fuck,” Younghyun breathes, and he says it like a prayer, like a word of worship.

“Like what you see?” murmurs Sungjin.

Younghyun nods. “Yes, hyung.”

“Then why don’t you see how it feels?”

And so Younghyun does. He spits in his hand again, getting all of it wet, before curling it around the top of Sungjin’s cock. He swipes his thumb experimentally across the slit. Above him, Sungjin hisses.

“I wondered, you know,” starts Younghyun. He drags his fist down Sungjin’s length, excruciatingly slow.

“About?” Sungjin sounds slightly out of breath.

“How you would look, in my hand.”

When Sungjin next speaks, it sounds like it’s through gritted teeth. “Younghyun….”

Struck by a sudden idea, Younghyun asks, “Actually, hyung, could you turn your night light on?”

“Huh?”

“I wanna see you.”

Sungjin obliges, and a warm orange light envelops the space around his bed. “Better?”

“Yeah,” says Younghyun. Now he can see the finer things better: the veins running down the length of Sungjin’s cock. The contrast of it, red and leaking, against Sungjin’s creamy thighs and stomach. His balls, slightly furred and hanging heavy, begging to be fondled—and so Younghyun does. While his right hand maps out Sungjin’s length, his left cups and massages his balls.

“Younghyun-ah,” whines Sungjin, and Younghyun _lives._ He knows this isn’t nearly enough pressure to get a man off, but….

“Why’d d’you have to be so _hung_ , hyung?” groans Younghyun. It makes him want to touch and squeeze and taste and beg and more. Anything and everything, as long as he can get Sungjin to himself. “I can’t help myself when you have a cock like this.”

Sungjin starts to laugh but it turns into a moan when Younghyun thumbs the crown of his cock again.

“You can’t, can you?” he asks, purely rhetorical. Sounding rather conversational, he adds, “What else did you think about, Younghyun-ah?”

“How you would taste,” confesses Younghyun, and in spite of himself the grip of his slow strokes around Sungjin tightens just a tad. He sniffs and fuck, he can already smell it—spearmint soap and Sungjin’s natural musk. They urge Younghyun on. “How you would feel in my mouth. You’re so _much_ , Sungjin-hyung, I want to know if I can take you. Fuck, hyung, I….” He looks up at Sungjin, pleading.

Sungjin’s hot gaze softens. “You don’t have to wonder, Younghyun-ah.”

He takes one side of Younghyun’s face with a hand, his thumb caressing the cheek. Younghyun presses closer, seeking contact.

“Go on,” says Sungjin in a terribly casual voice, withdrawing his hand.

“Can I? Can I really?” Younghyun’s voice is that of a man who has been handed the key to everything he could ever want.

Sungjin smiles, slow and lovely. “Really. I’m all yours.”

The words land like a punch straight to Younghyun’s gut. There are so many things he could do, but he starts with small kitten licks of Sungjin’s exposed tip, recalling his reaction. As expected, Sungjin tenses up as soon as Younghyun starts focusing there. It’s salty, and the smooth flesh is warm where it meets his tongue. Each flick of Younghyun’s tongue against the slit seems to wind Sungjin up more and more, and every so often he groans something undecipherable.

But it would be a waste if he doesn’t take Sungjin all the way, and so Younghyun gathers spit in his mouth before wrapping his lips around the head, hollowing his cheeks, and starting to descend.

Sungjin seems to realize his intent once he’s completely filled Younghyun’s mouth. “Younghyun-ah, it’s alright if—”

Younghyun levels him with the nastiest glare he can muster while sucking someone off.

The laugh that bubbles out of Sungjin sounds awfully resigned. “Just don’t hurt yourself, okay?”

The note of concern in Sungjin’s voice sparks a fire in Younghyun’s veins. It makes him want to try harder, uncaring of the slowly building ache in his jaw, the spit starting to leak at the corners of his mouth. Sungjin is so long the halfway point of his cock is already in Younghyun’s throat, but he has always loved a big dick and a challenge. He breathes through his nose, allowing his throat to relax, and takes Sungjin in further.

Sungjin, for his part, seems to be the paragon of self-control, barely twitching forward as Younghyun stretches to accommodate him. It helps that he’s seated, but Younghyun would know—anyone with less self-discipline would be bucking their hips by now.

Finally, Younghyun bottoms out, Sungjin’s cock buried to the hilt in his mouth, his nose flush against the curly hairs at its base. Spearmint and sex, all that much stronger, flooding his senses.

“God, Younghyun, you—” Sungjin grits out, and then Younghyun deliberately swallows around him, and Sungjin’s sentence ends in a long groan.

Younghyun looks up, hoping his eyes adequately convey the message of _I told you so,_ before bracing one hand on Sungjin’s hip and beginning to withdraw. Sungjin’s thighs tense, his breathing becoming shallow.

It’s the moment on a rollercoaster right before the drop, and Younghyun doesn’t give any warning when he takes the plunge. He sucks Sungjin’s cock in earnest, bobbing up and down the slick length now that he’s given his throat some time to acclimatize. Sungjin’s groans become louder, more undignified, as Younghyun works up and down his fat cock, almost pulling off entirely and then swallowing him up again.

Younghyun never really feels as grand as he does when he’s got a cock of this size in his mouth. But even he can admit this is a little different—this is Sungjin’s cock that he’s talking about. It’s big, yes, but more importantly it’s _Sungjin’s_. Younghyun moans at the thought, making the man above him moan, too.

 _Hyung, do you like it? Do you like it as much as I do?_ Questions such as those come up in Younghyun’s mind, but he can’t ask them because his mouth is otherwise occupied.

As he fights the urge to gag, tears start to prick the corners of his vision, but all the constriction does for Sungjin is make him moan louder, longer. Younghyun blinks the wetness in his eyes away and looks up at Sungjin, who’s regarding him like he’s a thing of wonder. Younghyun hollows his cheeks, relaxes his throat, redoubles his efforts.

Their room fills with the wet sounds of sex, the colorful barrage of curses that leaves Sungjin’s lips, the muffled moans Younghyun can’t help but let out.

“Younghyun-ah,” says Sungjin in warning, starting to lose control of his hips. “I’m close, do you wanna—”

Younghyun would shake his head if he could, but as it is, he merely sucks his cheeks further in and swallows around Sungjin’s cock to say no.

“Fucking hell, Younghyun,” growls Sungjin lowly, and his hips continue to buck forward, the most he can while he’s seated.

Younghyun groans, looking right in Sungjin’s eyes, hoping he would get the message. _Go on, do it, as much as you can, take me._

Sungjin, nodding once, starts to shallowly fuck Younghyun’s waiting mouth. Younghyun, ever the people pleaser, meets him thrust for thrust. He tamps down on his gag reflex, ignores the aching of his jaw. A litany of curse words intermingled with appellations to Younghyun dribble from Sungjin’s lips, and the sound of it is a symphony to Younghyun’s ears.

“Younghyun, fuck, Younghyun,” gasps Sungjin, sounding breathless. “I’m gonna—”

His hips start to stutter, losing their rhythm, and before Younghyun knows it, Sungjin is coming hot and bitter in his mouth. Younghyun swallows it down the best he can, not wanting to lose a drop of it. Sungjin startles, oversensitive, as Younghyun drinks him in.

“Shit, okay. That’s enough, Younghyun-ah,” he says, gently pushing Younghyun up and off his cock. He whines. It makes Sungjin smile.

“Thank you,” says Younghyun hoarsely. He wipes his tears with the sleeves of his shirt and the spit that dribbled down his chin with the hem.

“Why are you thanking me?” Sungjin sounds utterly bewildered. “I should be thanking _you_.”

“No, hyung. I mean it. I love your cock, I want it in me,” Younghyun confesses, sounding reverent. “Fuck my face next time, please, Sungjin-hyung?”

Sungjin is rendered speechless for a few seconds before coming back to himself. “W-we’ll get to that later. Now… come here, Younghyun,” he says, patting his thighs. “Let me take care of you, too.”

Between those words, the heat in Sungjin’s gaze as he meets Younghyun’s eyes, and the fact that he has never been this aroused in his life, Sungjin’s sure strokes undo him in a matter of minutes.

Younghyun collapses onto Sungjin’s lap, and as Sungjin continues to toy with him idly, he whines into the crook of Sungjin’s neck. “S-Sungjin-hyung….”

“Too much?” Younghyun thinks he hears a faint chuckle, the damn sadist. “Sorry,” adds Sungjin for good measure.

When Younghyun pulls away, it’s to see Sungjin licking his hand clean of Younghyun’s come. If he hadn’t just come a minute ago, the sight of it would have had him filling up again.

“What?” Sungjin asks, seeing Younghyun’s slack-jawed reaction. “You’re not the only one who doesn’t wanna let _that_ go to waste.”

“That’s hot,” offers Younghyun lowly, smirking.

“Not as hot as you,” replies Sungjin. His eyes zone in on Younghyun’s mouth. It must be red and swollen from the use. “What the fuck, Younghyun. I’d… I’d never had someone who could take all of me.”

“Can I do it again?” asks Younghyun, eagerly coming closer.

Sungjin chuckles. “Of course. Fuck. You’re really something else, Younghyun-ah.”

Younghyun favors him with a mischievous grin. “I’m an overachiever, hyung,” he says proudly. “It doesn’t matter if there’s a challenge—I’ll always suck seed.”

**Author's Note:**

> With apologies to [Childish Gambino](https://open.spotify.com/track/6Rs79BpoJYdQpbMXP41I3B?si=m5FCzLzdSe2S0Mn0r1w1Eg).


End file.
